How can I diagnose which `git` magit is running?

Question

I'm trying to use Magit with TRAMP. The remote host has multiple git versions, necessitating

(add-to-list 'tramp-remote-path "/usr/sup/bin")

in my .emacs. However, when I run magit-status in a TRAMP buffer, I get this error message in *Messages*:

magit-insert-head-branch-header: Wrong type argument: stringp, nil

And it is accompanied by this message in *Warnings*:

Error (magit): Magit requires Git >= 2.0.0, but on /ssh:nr@homework: the version is 1.8.3.

If multiple Git versions are installed on the host, then the
problem might be that TRAMP uses the wrong executable.

First check the value of `magit-git-executable'.  Its value is
used when running git locally as well as when running it on a
remote host.  The default value is "git", except on Windows
where an absolute path is used for performance reasons.

If the value already is just "git" but TRAMP never-the-less
doesn't use the correct executable, then consult the info node
`(tramp)Remote programs'.

Information about the context:

• The value of magit-git-executable is "git".

• The value of tramp-remote-path is ("/usr/sup/bin" tramp-default-remote-path "/bin" "/usr/bin" "/sbin" "/usr/sbin" "/usr/local/bin" "/usr/local/sbin" "/local/bin" "/local/freeware/bin" "/local/gnu/bin" "/usr/freeware/bin" "/usr/pkg/bin" "/usr/contrib/bin" "/opt/bin" "/opt/sbin" "/opt/local/bin").

• On the remote host, there is a /usr/sup/bin/git with version 2.19.1.

My question: how I can figure out the absolute pathname of the git that Magit is running on the remote host?

Possibly relevant question: magit with tramp is not working with git correctly

Answer 1

If the value already is just "git" but TRAMP never-the-less doesn't use the correct executable, then consult the info node `(tramp)Remote programs'.

Did you do that? It says:

When remote search paths are changed, local TRAMP caches must be recomputed. To force TRAMP to recompute afresh, exit Emacs, remove the persistent file (*note Connection caching::), and restart Emacs.

And you would probably use:

6.6 Cleanup remote connections

TRAMP provides several ways to flush remote connections.

-- Command: tramp-cleanup-connection vec This command flushes all connection related objects. ‘vec’ is the internal representation of a remote connection. When called interactively, this command lists active remote connections in the minibuffer. Each connection is of the format ‘/method:user@host:’. Flushing remote connections also cleans the password cache (*note Password handling::), file cache, connection cache (*note Connection caching::), and connection buffers.

-- Command: tramp-cleanup-this-connection Flushes only the current buffer’s remote connection objects, the same as in ‘tramp-cleanup-connection’.

-- Command: tramp-cleanup-all-connections Flushes all active remote connection objects, the same as in ‘tramp-cleanup-connection’.

-- Command: tramp-cleanup-all-buffers Just as for ‘tramp-cleanup-all-connections’, all remote connections are cleaned up in addition to killing buffers related to that remote connection.